Optimization and Responsive Adaptation of a Gamified eLearning Website -- 2

Our company "Unlimited Educational Services" has designed a brand new eLearning website based on the concept of gamification and used many gamification elements [login to view URL] website is designed for primary level students so the graphical layouts based on that age group with some basic animations and age appropriate design. Please find more details below ; Our website has 5 pages. 4 of them simple and last one is our main page. Main page have 12-15 pop-ups and have around 15 animations (css, jquery). It is about gamification, so it is graphic based. We are looking for a Front End Web developer to apply cross-browser, responsive and performance optimization to our existing web site. Css animation, Jquery Animate, Bootstraps and Sprite-image logic are must. Cross-browser optimization have to be identically except browser type and version resdirections. These resdirections must handle by similar working principles. Browsers: Chrome (Build 40.x and newer), Firefox (Build 42.x and newer), Safari (8.x and newer), Opera (Build 12.1 and newer), IE (8-9-10-11), Yandex Browser and Microsoft Edge. Mobile Browsers: Chrome Mobile, Opera Mini, IE, Safari, Firefox, Android Browser, Yandex Mobile Minimum screeen Resolution for responsive optimization : 360x640 Skills Needed: HTML5, CSS3, Javascript, Jquery, Bootstraps